// Project: Recursion
// Module: hanoi1
// Source code file: Main.java
// Solve the Towers of Hanoi Puzzle 
// using the standard recursive algorithm.

public class Main
{
    public static void main(String[] args)
    {
        int nDisks;

        try {
            nDisks = Integer.parseInt(args[0]);
            hanoi(nDisks, "A", "B", "C");
        }
        catch(NumberFormatException e) {
            System.out.println(
                "Illegal input for number of disks.");
        }
    }

    public static void hanoi(
        int n, String from, String to, String aux) {
        if (n >= 1) {
            hanoi(n - 1, from, aux, to);
            System.out.println(from + " to " + to);
            hanoi(n - 1, aux, to, from);
        }
    }
}